It is well known in motor vehicles to provide an air bag module mounted beneath an opening in the instrument panel. The module typically includes a metal housing having opposing side walls and end walls defining an air bag deployment opening. The module also typically includes an air bag having a mouth portion mounted to the housing by an air bag retainer. The air bag retainer typically has retainer apertures which must be aligned with corresponding air bag apertures on the mouth portion of the air bag. Since the air bag is a flexible material, the air bag retainer is needed to provide support to the mouth portion of the air bag and to stiffen the mouth portion of the air bag for easier attachment of the air bag to the housing. The housing has housing apertures which must be aligned with the retainer apertures and air bag apertures so that fasteners' can be inserted through all three sets of aligned apertures to attach the air bag and retainer to the housing. An inflator is mounted beneath the air bag in the housing and discharges inflator gas to inflate the air bag when sensing predetermined vehicle conditions. The opening in the instrument panel is typically covered by a hinged cover door which is forced open by the deploying air bag.
Numerous air bag retainers are known in the prior art for attaching the mouth portion of the air bag to the housing. Many of these air bag retainers are generally rectangular frames that are attached to either the inside or outside of the housing. During air bag deployment, the discharging inflator gas pressurizes the housing and normally causes the walls of the housing to bulge outward or "bellmouth" during air bag deployment. It is also known that some air bag retainers mounted on the housing may provide structural support to the housing walls to reduce the amount of bellmouthing.
Due to variations in manufacturing tolerances, many prior art air bag retainers have the shortcoming of being difficult to fit flush against the walls of the housing and also difficult to align the retainer apertures and air bag apertures with the housing apertures during assembly. To overcome this shortcoming, the prior art has suggested air bag retainers which are a frame formed of a plurality of pieces held together by fasteners and which are adjustable or slidable relative each other such that the size of the air bag retainer can be adjusted during assembly to the housing. However, such an air bag retainer has many shortcomings such as having numerous components, being expensive to manufacture and assemble, having increased mass, and being difficult to adjust during assembly due to the numerous components of the retainer.